1. Field of the Invention
The present invention relates to low friction, incompressible energized gas particle bearings for separating mating surfaces at near zero coincident velocities.
2. Description of the Prior Art
Bearings utilizing grooves formed in one face to permit a lubricating fluid to be carried onto lands that are formed between the grooves to provide a lubricating film under high relative surface speeds are known. A problem however, is getting the surface to separate or "lift off" before galling or other damage results. Early work in groove type hydrodynamic bearings of this form was carried out by E. A. Muijderman who holds a number of early U.S. patents in the hydrodynamic bearing area. For example, U.S. Pat. No. 3,328,094 issued to Muijderman on Jun. 27, 1967 shows an axial thrust bearing that includes shallow grooves in at least one of the mating members. A lubricant (not a gas specifically) is provided and it is pushed from the outer side of the bearing to the inner side by the grooves as rotation between the two parts occurs. An energized film is created between the members of the bearings as the parts rotate.
U.S. Pat. No. 3,154,353, also issued to Muijderman, which has grooves between the mating parts, relates primarily to having a cavity that is formed in a curve with an axis rotation in each instance. The grooves are formed to provide a lubricant "pump" so that upon rotation the lubricant is forced between the mating surfaces.
An additional type of self-pumping hydrodynamic bearing is shown in U.S. Pat. No. 4,573,810, issued Mar. 4, 1986 to Fust et al., wherein gently tapered lead-in surfaces are provided on sides of a groove that serves as a lubricant storage groove. This has particular adaption in connection with lubricating a belt passing through the system. However, a teaching of true operation of hydrodynamic bearing utilizing spiral grooves is missing, and the ability to provide lift-off between the individual parts at very low movement is not taught.
A comprehensive technical work relating to spiral groove bearings is in a book entitled "Spiral Groove Bearings" by E. A. Muijderman, Phillips Technical Library (1966) (Library of Congress Card Catalog No. 66-19020). Equations for predicting hydrodynamic bearing characteristics are provided.